The Federal Reserve will keep winding down one of its highest-profile easy-money programs unless the economy takes a serious turn for the worse, Janet Yellen said in her inaugural public appearance since becoming the central bank's first chairwoman.

Some recent economic data have been soft, Ms. Yellen noted in her steady-as-she-goes comments before the House Financial Services Committee, but she doesn't want to overreact to that. She promised overall to press ahead with the policies of her predecessor as Fed chief, Ben...